In general, digital broadcasting services provide multichannel and multimedia broadcasting with higher quality of service in terms of video and audio quality than analog broadcasting services. Further, digital broadcasting services also provide multifunctional and interactive broadcasting where multimedia contents are provided by the broadcasting channel with more efficient bandwidth usage. For interactive broadcasting services, it is required to enable data transmission between broadcast receiver and remote data server using data return channel.
In digital broadcasting services, a CAS (Conditional Access System) for enabling conditional access and regional restriction may be established through data transmission using return channel between broadcast receiver and remote CAS data server. Under CAS system, broadcasting services may be available by periodically transmitting and receiving CAS-related “key” through data transmission between CAS server and broadcast receiver.
A CAS system, together with a subscriber management system, is an essential system for providing subscription-based broadcasting services. In contrast to terrestrial broadcasting system for providing TV program to unspecified people, a CAS system allocates individual or group address to each subscriber to provide subscriber-specific TV program or other services with more accuracy and convenience. Various additional services including pay-per-view (PPV) and near-video-on-demand (NVOD) may be provided through the usage of CAS system.
FIG. 1 illustrates a conventional CAS system for digital mobile TV (DMTV) broadcasting.
The smart device 103 such as smart phone, smart pad and tablet PC may receive broadcasting signal 104 and generate direct return channel 102 for transmitting and receiving data to and from a remote data server 101 using internal Internet access capabilities. User profile information such as subscriber administration data and subscriber's propensity for TV program may be collected in the remote data server 101 via the direct return channel 102 generated by the smart device 103.
Since collection of user profile information is essential to MDTV broadcasting business in commercial sense it is required to secure a data return channel from a mobile digital broadcast receiver to the remote data server. Currently, MDTV broadcasting service providers use Internet channel using WiFi or 3G data communications as data return channel, and thus the smart devices 103 having internal WiFi and 3G data communications capabilities haven been selected as optimal receivers for MDTV broadcasting services.
However, other types of mobile digital broadcast receivers without internal Internet capabilities such as portable DVD player, portable navigation device (PND), car AV box, portable game terminal and other type of multimedia display devices may not be used as the mobile digital broadcasting receiver since they are not supported with WiFi or 3G data communications for Internet connection.
It is needed to employ internal or external Internet access capabilities to the existing mobile digital broadcast receiver without internal Internet access capabilities to provide mobile digital broadcasting service with CAS, which incurs additional manufacturing cost to device manufacturers for internal module and additional expenses to users for external module. The cost increase has been a non-negligible business obstacle in providing digital mobile broadcasting services with CAS to both industry and users.